This invention generally relates to the lining of articles particularly to a method and arrangement for lining melting ovens.
A procedure for finishing a melting oven is known wherein the melting oven is provided with a refractory lining using a ramming mass which is sintered in order to convert it into a unitary mass constituting the lining of the oven. A metal form or mold member is utilized to confine the initially particulate ramming mass. The mold member is of smaller dimensions than the oven chamber to be lined, is inserted into the oven chamber so that a space is defined between the mold member and the inner wall of the chamber. The ramming mass is poured in this space and thereafter sintered.
It has been proposed to use a mold member which is coated with a refractory composition hardenable at temperatures which do not cause the metal member to be corroded or attacked. The mold member coated with hardened refractory composition is arranged in a melting oven so that a space is provided between the hardened composition and the inner surface of the oven chamber, the ramming mass is admitted into the space defined between the hardened composition and the inner wall of the oven chamber, the mold member is removed from the hardened composition which remains in the chamber as the sole support for the ramming mass which latter is thereafter rigidified to be converted into the lining of the oven. The mold member removed from the hardened composition, can be re-used as often as desired.
The rigidification of the lining substance is performed by sintering or vitrification of the ramming mass with use of the following methods proposed in the art. After preparation of the oven, the latter is slowly heated either by an inductively heated metallic insert inserted into the oven, or by gas flame. The above preheating is continued approximately from 4 to 6 hours until the oven is heated to red heat. After the above preheating the thus preheated oven is filled with liquid metal so as to heat the oven approximately from 1300.degree. C. to 1550.degree. C. to thereby sinter the ramming mass. It is also possible to continue the inductive heating of the metallic insert so as to melt the latter. In the latter case, the oven is filled with an additional metallic cover and the lining is sintered at 1550.degree. C. The process of sintering itself is being continued approximately from 1 to 2 hours.
In accordance with the known method and arrangement, the refractory hardenable composition surrounding the mold member and insertable together with the latter into the oven, is made by coating the mold member with the composition in flowable state and hardening the latter on the mold member so as to form a circumferentially complete refractory member. This has the disadvantage that the above method is essentially labor-consuming and time-consuming especially taking into consideration the fact that in order to form a substantially thick layer of the refractory hardenable composition a plurality of thin layers must be successively applied onto the mold member to thereafter be sintered.
The step of rigidification of the ramming mass is also labor-consuming and time-consuming since it requires the above mentioned preheating of the oven to be lined. Due to the fact that the process of lining requires in this case essentially great time, the lining is usually performed only during week ends which results in that sometimes the not lined ovens wait until week-end and are not in operation.